1. Technical Field
The present invention relates to an inductively coupled plasma processing apparatus, and more particularly to an inductively coupled plasma processing apparatus, in which a linear antenna creating an electric field is accommodated in a reaction chamber for carrying out a plasma etching process over a large area.
2. Description of the Related Art
Generally, an inductively coupled plasma (ICP) processing apparatus includes a spiral type antenna, which is installed at an upper outer portion of a reaction chamber by interposing dielectric material between the spiral type antenna and the reaction chamber performing a plasma etching process. When induced radio frequency power is applied to the spiral type antenna, an electric field is created in the reaction chamber, thereby generating plasma in the reaction chamber. The ICP processing apparatus has a simple structure as compared with structures of ECR (Electron cyclotron resonance) and HWEP (Helicon-wave excited plasma) processing devices, so the ICP processing apparatus can generate plasma over a large area with a relatively simple manner, so that the ICP processing apparatus is widely used and developed.
A spiral type ICP source has been widely used as an antenna source for obtaining high-efficiency and high-density plasma. FIG. 1A is a schematic view showing a conventional ICP chamber. An antenna source is positioned at an uppermost part of the ICP chamber such that it is exposed to an exterior. In addition, dielectric material is positioned between the ICP chamber and the antenna source so as to insulate the antenna source from the ICP chamber while maintaining a vacuum state. FIG. 1B is a view showing a shape of a spiral type antenna source used in the ICP chamber. However, the spiral type antenna source causes problems as the size of the ICP chamber is enlarged. Firstly, size and thickness of dielectric material, which maintains the vacuum state between the antenna source and the ICP chamber, are increased as the ICP chamber is enlarged, thereby increasing the manufacturing cost. In addition, since a distance between the antenna source and plasma is remote from each other, plasma efficiency is lowered. Moreover, a length of the antenna source is correspondingly increased as the ICP chamber is enlarged, so power loss is caused due to resistance of the antenna source and an evenness of the spiral type antenna source is created. In addition, if a power supply applying RF power of 13.56 MHz to the ICP chamber is used, a standing wave effect occurs in a source corresponding to a half wavelength of 13.56 MHz.